The difference: 160 tube length objective lens can not change its optical distance, and infinity objective lens can be added to other devices; such as the biological microscope if it is infinitely objective lens, then you can add fluorescent device, but the 160 tube length objective lens, then not.

Objectives are the most important optical components of a microscope. Using light to image the object for the first time directly affects the quality of the imaging and various optical specifications and is the number one criterion for measuring the quality of a microscope. The structure of the objective lens is complicated and made precisely. Due to the poor correction of the object, the metal lens barrel is composed of a lens group which is separated by a certain distance and is fixed. Objectives have many specific requirements, such as coaxial, parfocal. Parfocal is both in the microscopic examination, when using a magnification of the objective lens to observe the image is clear, the conversion of another magnification of the objective lens, its imaging should be basically clear, and the center of the image should also be within a certain range deviation , That is, the degree of hinge. The pros and cons of parfocal performance and the degree of co-axial is an important symbol of the quality of the microscope, it is related to the quality of the objective and the accuracy of the objective lens converter. Modern microscope objectives have reached a high degree of perfection, the numerical aperture is close to the limit, the resolution of the field of view of the center of the difference between the theoretical value has been minimal. However, the possibility of continuing to increase the field of view of the microscope objective and improving the imaging quality at the edge of the field still exists. Such research work is still under way. Modern microscope objectives differ in imaging points. Objectives are the most complex and important part of a microscope and work in wide beams (large apertures), but these beams have a small dip angle to the optical axis (small field of view); the eyepiece operates in a narrow beam but with a large dip Field large). When calculating the objective and eyepiece, there is a big difference in eliminating aberrations. The aberrations associated with wide beams are spherical aberration, coma, and positional aberration; the aberrations associated with the field of view are astigmatism, curvature of field, distortion, and magnification. Microscopic objective is a canceling spherical aberration system. This means that for a pair of conjugate points on the axis, there are only two such canceling spills for each objective when spherical aberration is eliminated and sinusoidal conditions are achieved. Therefore, any change in the calculated positions of the object and the image causes the aberration to become large.